Studies on the expression of recombinant human MCAF/GM-CSF fusion protein and its biological activities

With PCR technology and methods of DNA recombination in vitro, the fusion protein of GM-CSF with MCAF, the factor that has a directing effect on cells to a target was generated by the construction of recombinant plasmids pMG01, pMG02 and pMG03 with different nucleotide composition between its SD sequence and the initiation codon ATG under the control of lambda PRPL promoter of vector pBV220. Although no stable secondary structure exist in the translation initiation regions of all the recombinant plasmid constructed, the expression lapels of the products with DH5 alpha (pMG02) and DH5 alpha (pMG03) are much higher than that with DH5 alpha (pMG01) which hardly expressed the product. The assay of Western blot indicated that the expressed product reacted with MCAF and GM-CSF antibodies, respectively. The assay of biological activities showed that the expressed product had apparent monocyte chemoattractant activity and supported the growth of the human human GM-CSF-dependent cell line TF1, suggesting that the biological functions of MCAF and GM-CSF are compatible.